CVE-2026-10670: memory-safety in zephyrproject zephyr
The CONFIG_USERSPACE verification handler for the k_thread_name_copy() system call (z_vrfy_k_thread_name_copy() in kernel/thread.c) calls k_object_find() on the caller-supplied thread pointer and then dereferences the returned struct k_object without checking it for NULL. k_object_find() returns NULL whenever the supplied pointer is not a registered (static or dynamic) kernel object. The pre-fix guard tested thread == NULL instead of ko == NULL, so an unprivileged user-mode thread that invokes k_thread_name_copy() with any non-NULL but unregistered pointer (e.g. an arbitrary address) passes the NULL test, after which the verifier reads ko->type through a NULL pointer. Because the syscall verifier runs in supervisor mode, this NULL dereference is a kernel-mode fault that halts or reboots the system, allowing untrusted user code to crash the kernel across the userspace security boundary (denial of service). The marshaller passes the thread argument to the verifier without any prior K_SYSCALL_OBJ validation, so the bad pointer reaches the defect directly. The flaw affects builds with CONFIG_USERSPACE and CONFIG_THREAD_NAME enabled and has been present since the special-case lookup was introduced around v2.0.0; it is present in v4.4.0 and earlier. The fix changes the guard to check the k_object_find() return value (ko == NULL) before dereferencing it.
AI Analysis
Technical Summary
The vulnerability exists in the CONFIG_USERSPACE verification handler for the k_thread_name_copy() syscall in Zephyr. The verifier calls k_object_find() on a user-supplied thread pointer and dereferences the returned k_object without checking for NULL. If the pointer is not a registered kernel object, k_object_find() returns NULL, but the verifier incorrectly checks the original pointer instead of the returned object pointer. This leads to a NULL pointer dereference in kernel mode, causing a system crash or reboot. The flaw affects builds with CONFIG_USERSPACE and CONFIG_THREAD_NAME enabled and has been present since around version 2.0.0. The fix involves correcting the NULL check to verify the k_object_find() return value before dereferencing.
Potential Impact
An unprivileged user-mode thread can cause a kernel-mode NULL pointer dereference by passing an invalid thread pointer to k_thread_name_copy(). This results in a denial of service condition by crashing or rebooting the system. There is no impact on confidentiality or integrity, only availability is affected.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. The fix involves changing the NULL pointer check in the syscall verifier to correctly check the return value of k_object_find() before dereferencing it. Until a patch is applied, avoid enabling both CONFIG_USERSPACE and CONFIG_THREAD_NAME simultaneously if possible, or restrict unprivileged user-mode threads from invoking k_thread_name_copy() with arbitrary pointers.
CVE-2026-10670: memory-safety in zephyrproject zephyr
Description
The CONFIG_USERSPACE verification handler for the k_thread_name_copy() system call (z_vrfy_k_thread_name_copy() in kernel/thread.c) calls k_object_find() on the caller-supplied thread pointer and then dereferences the returned struct k_object without checking it for NULL. k_object_find() returns NULL whenever the supplied pointer is not a registered (static or dynamic) kernel object. The pre-fix guard tested thread == NULL instead of ko == NULL, so an unprivileged user-mode thread that invokes k_thread_name_copy() with any non-NULL but unregistered pointer (e.g. an arbitrary address) passes the NULL test, after which the verifier reads ko->type through a NULL pointer. Because the syscall verifier runs in supervisor mode, this NULL dereference is a kernel-mode fault that halts or reboots the system, allowing untrusted user code to crash the kernel across the userspace security boundary (denial of service). The marshaller passes the thread argument to the verifier without any prior K_SYSCALL_OBJ validation, so the bad pointer reaches the defect directly. The flaw affects builds with CONFIG_USERSPACE and CONFIG_THREAD_NAME enabled and has been present since the special-case lookup was introduced around v2.0.0; it is present in v4.4.0 and earlier. The fix changes the guard to check the k_object_find() return value (ko == NULL) before dereferencing it.
CVSS v3.1
Score 5.5medium
Affected software
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability exists in the CONFIG_USERSPACE verification handler for the k_thread_name_copy() syscall in Zephyr. The verifier calls k_object_find() on a user-supplied thread pointer and dereferences the returned k_object without checking for NULL. If the pointer is not a registered kernel object, k_object_find() returns NULL, but the verifier incorrectly checks the original pointer instead of the returned object pointer. This leads to a NULL pointer dereference in kernel mode, causing a system crash or reboot. The flaw affects builds with CONFIG_USERSPACE and CONFIG_THREAD_NAME enabled and has been present since around version 2.0.0. The fix involves correcting the NULL check to verify the k_object_find() return value before dereferencing.
Potential Impact
An unprivileged user-mode thread can cause a kernel-mode NULL pointer dereference by passing an invalid thread pointer to k_thread_name_copy(). This results in a denial of service condition by crashing or rebooting the system. There is no impact on confidentiality or integrity, only availability is affected.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. The fix involves changing the NULL pointer check in the syscall verifier to correctly check the return value of k_object_find() before dereferencing it. Until a patch is applied, avoid enabling both CONFIG_USERSPACE and CONFIG_THREAD_NAME simultaneously if possible, or restrict unprivileged user-mode threads from invoking k_thread_name_copy() with arbitrary pointers.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- zephyr
- Date Reserved
- 2026-06-02T15:25:33.216Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a56533f68715ace43bba7c3
Added to database: 07/14/2026, 15:18:23 UTC
Last enriched: 07/14/2026, 15:37:43 UTC
Last updated: 07/14/2026, 15:48:09 UTC
Views: 3
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